Electrolytic device and method of making same



M .J. B. BRENNAN ETAL ELECTROLYTIC DEVICE AND METHOD OF MAKING' SAME pril 21% 19 Filed Aug 20 36 Q5171 m l INVENTORS;

ATTORNEYS BY. fO/VA MA 7 flj Patented Apr. 29, 1941 OFFICE ELECTROLYTIC DEVICE AND METHOD OF MAKING SAME Joseph B. Brennan and Leona Marsh, Fort Wayne,

Ind.; said Marsh assignor to Joseph B. Brennan, Fort Wayne, Ind.

Application August 20, 1936, Serial No. 96,976

4 Claims.

This invention relates to electrolytic devices such as electrolytic condensers, rectifiers and the like, and more particularly to the provision of a vent and seal for allowing the escape of as generated in the operation of the device while preventing the escape of the electrolyte. Electrolytic condensers and similar devices of the type embodying one or more filmed electrodes generate gas under some conditions of operation. Therefore the containers for the electrolyte and electrodes should be provided with vents for relieving pressure of the gas, and the containers should also be sealed to prevent leakage of the liquid electrolyte, particularly during shipment of the condensers.

It is among the objects of our invention to provide an emcient vent and seal for electrolytic condensers and similar devices which will function to 'permit escape of gases from the condensers and to prevent leakage of electrolyte during shipment and during all ordinary conditions of operation. Another object of our invention is to provide a vent and seal which can be constructed and incorporated in condensers or similar devices at low cost. Another object is to provide a simple and economical method of making vents for electrolytic condensers and similar devices.

Further objects and advantages of our inven-' tion will become apparent from the following description of preferred forms thereof, reference being made to the accompanying drawing. The

essentialcharacteristics are summarized in the claims.

Ourinvention is described herein as applied to a well known type of electrolytic condenser which comprises a tubular container of aluminum or other suitable material which retains the electrolyte and which may act as the cathode of the condenser. The anode is suitably supported within the container, the anode terminal ordinarily projecting out of the bottom of the container. The upper end of the container is ordinarily closed by a flanged cap of aluminum or other suitable metal, the peripheral edge of which is spun downwardly into engagement with the condenser to retainthe cap thereon.

Briefly, a preferred form ofv our invention as applied to the above described type of condenser includes a vent in the cap or closure member formed by perforating the central portion thereof and placing a flexible valve member such as a thin rubber disc having a small opening therein immediately beneath the perforation in the cap.

The rubber disc may be initially held in place i by a metal to rubber glue or cement. The rubber disc or other valve member is retained in position by means of a thin coating of rubber latex or other suitable material, which preferably covers the under surface of the cap and the rubber disc. The latex adheres to the aluminum cap sufficiently to retain the rubber disc in position, and as the layer of latex extends to the peripheral edges of the cap, it effectively seals the joint between the container and cap when the cap is spun down into engagement with the container thus replacing a gasket at the cap to can seal.

Before spinning the cap on the can the rubber disc covered with a thin layer of latex and securely held in place, may be perforated with a needle or, if desired, the rubber disc may be perforated before applying the latex, the thin latex film sealing the opening in the rubber disc so that none of the electrolyte can escape from the container during shipment regardless of the position of the condenser. In use the pressure of the gas generated within the condenser is sufficient to rupture the thin latex film overlying the perforation in the rubber disc, thus allowing the gas to escape through the perforation in the rubber disc and the registering opening in the cap.

A preferred form of our invention as applied to a conventional type of condenser is illustrated in the drawing in which Figure 1 is a vertical cross section through a condenser embodying our vent and seal; Figure 2 is a section illustrating the closure member; Figure 3 is a sectional view of the closure member showing the rubber sealing disc retained in position by the latex film; and Figure 4 is a fragmentary illustration of the upper portion of the container before the closure member has been applied thereto.

As shown in the drawing, the condenser may comprise a container i0 which forms the cathode of the condenser and within which the electrolyte H and the filmed anode l2 are disposed. The anode is supported within the container by the terminal or riser I3 which projects downwardly through a rubber collar or gromet M, the rubber collar being pressure fitted within the neck i 5 of the condenser to form a liquid tight joint and to support the riser or terminal in a vertical position. The condenser may be mounted in an aperture in a plate P by means of a spring clip 9 engaging grooves 8 in the neck l5, as described in the application of Joseph B. Brennan, Serial No. 52,502, filed December 2, 1935, and having a projecting ear I adapted for connection to a wire. A porous spacer Illa of insulating material may be disposed adjacent the inner surfaces of the cathode to prevent any possibility of contact between the anode and cathode. At its upper end the container is provided with a flanged portion l6 for engagement with the flange I! of the cap or closure member l8, the flanges i6 and i! being rolled or spun downwardly and inwardly to secure the cap or cover i8 to the upper open end of the container.

. move 'any tackiness of the latex.

To form a valve or vent which will allow gas to escape as required from the container and at the same. time prevent the leakage of electrolyte from the container during shipment and during ordinary usage of the condenser, the cap I8 is preferably provided with a hollow boss l9 which may be perforated as at 20. The hollow boss receives a suitable valve member such as the rubber disc 2| having a small perforation 22 preferably in the central portion thereof underlying the perforation 20 in the cap.

To retain the rubber disc 2| in position, the

\under side of the cap I8 is provided with a thin coating 23, preferably of latex, although other suitable materials such as nitro-cellulose lacquers or synthetic resins may be employed. The

"layer or film 23 preferably covers the entire under surface of the cap l8 including the under surface of the flanged portion H. In the case of latex, the layer may be easily applied to the disc by spraying liquid latex in finely divided form in a manner well known to those skilled in the art. The latex may then be cured by exposing the sprayed discs to a temperature of about 80 to 100 degrees centigrade and maintaining them at this temperature for a period of about thirty minutes. time depends on the kind of latex or other adhesive used and method of application. This operation produces a tough adherent layer which effectively retains the rubber disc 2| in position and serves as a gasket. Various other methods, such as brushing or dipping, may be employed 'to produce the film 23, but we have found the spraying method to be particularly effective and economical. Boric acid may be substituted for or used in addition to the heating to cure or re- This is accomplished by dusting powdered boric acid on the layer of latex and allowing it toset for some minutes and then dusting off the excess.

Thereafter the cap may be assembled onto the container by spinning or rolling the flange ll downwardly and inwardly as indicated at 25 in Figure -1. It will be noted that the layer of latex on the under side of the flange 11 forms a seal between the upper flanged portion I6 of the container and the cap, thus preventing any fluid from escaping through the joint between the cap and the container. The assembled condenser is sealed against the escape of electrolyte by reason of the fact that the small perforation in the rubber disc is closed even if perforated after applying the latex and thus the condenser may be shipped and handled without appreciable leakage taking place.

In service, -condensers of this type are ordinarily installed in a vertical position as shown,

the level of the electrolyte being somewhat below the top of the container. In this position the electrolytedoes not contact the under surface of the cap, and if gas is generated during the operation of the condenser, the pressure of the gas will expand the rubber disc in the. region adjacent the perforation 22 in the rubber disc, thus permitting gas to escape through the perforation 22 and the perforation 20 in the cap before the pressure is built up to suflicient extent to cause any damage to the condenser. Only small amounts of gas are generated and while the opening in the latex film and disc is large enough to permit discharge of the generated gases without the building up of excessive pressure, it is ordinarily so small as to substantially prevent the escape of liquid therethrough in the ordinary handling of the condenser even though the condenser is inverted so that the electrolyte comes in contact with the cap.

From the foregoing description of a preferred form of our invention, it will be evident that an extremely simple vent and seal for electrolytic devices such as electrolytic condensers is obtained. Our vent and seal effectively prevents the loss of electrolyte during shipment and ordinary handling of the condensers while permitting the gas generated by the operation of the condenser to escape substantially as fast as they are formed. Our vent and seal can be produced at very low cost by the method disclosed herein, and condensers embodying our vent and seal can be economically assembled.

Various modifications and changes in our invention will be apparent to those skilled in the art. It is therefore to be understood that our invention is not limited to the preferred form described herein or in any manner other than by v the scope of the appended claims when given the The temperature andrange of equivalents to which our patent may be entitled.

This vent may also be applied to dry type electrolytic condensers and also to other electrolytic devices.

We claim:

1. In an electrolytic device, a container having a flanged open end, a cap forming a closure for said container, said cap having an upwardly extending hollow boss having an opening therethrough, a perforated rubber member disposed in engagementwith the inner surface of said boss adjacent said opening, and a fllm of flexible material adhering to the under side of said cap in the region immediately adjacent said disk for retaining said member in position.

2. A closure member for electrolytic devices comprising a thin disc having a peripheral flange adapted tobe placed into engagement with a container, a perforated hollow boss, a rubber valve member disposed within said hollow boss and in engagement with the inner surface thereing in contour to and engaging substantially the entire under surface of said closure member and adapted to retain said valve member in position and to form a seal when the engaging portion of said valve member is placed into engagement with the open end of the container.

3. A method of making vents for electrolytic devices including the steps of forming a closure member having an opening therein, positioning an elastic disc on the surface of said closure member adjacent said opening, spraying a thin adherent layer of latex over the elastic disc and the adjacent surfaces of the metallic disc and thereafter perforating the elastic disc.

4. A method of making venting and sealing means for an electrolytic condenser or similar device of the type embodying a container having an open end, including the steps of forming a closure member for the container having a perforation therein, placing a perforated rubber disc in engagement with said closure member adjacent the perforation therein, coating the surface 

